The importance of Muscular Strength: a brief summary
From a review article (2018)
The new year has started with a fantastic review by Timothy J. Suchomel et al. [1] about physiological determinants of muscle strength, periodization, resistance training methods, loading strategies, exercise sets and rest intervals considerations. For the full text look at the reference at the end of the post.
In this blog post I will summarize the article by reporting some nuggets from the text
Physiological Factors Affecting Muscular Strength
Muscle Hypertrophy and Architecture
Evidence suggests that an order of first increasing the muscle’s cross-sectional area (CSA) (i.e., hypertrophy) and work capacity (i.e., force production capacity), followed by a subsequent phasic progression, can produce superior strength-power gains. Alterations in skeletal muscle hypertrophy can greatly impact a muscle’s ability to produce force and power.
Research indicated that strong relationships (r = 0.70) existed between muscle CSA and greater force production. Further literature suggested that muscle CSA increases and muscle architecture alterations may account for approximately 50–60% of the changes in force production following short-term resistance training (RT)
Musculotendinous Stiffness
Increased tissue stiffness (i.e., the relationship between a given force and the amount of stretch the tissue undergoes) can enhance force transmission. Therefore, tendon stiffness adaptations, as well as the structures within the muscle (e.g., actin, myosin, titin, and connective tissue), can influence muscular strength and associated characteristics such as rate of force development (RFD) and power
Motor Unit Recruitment
It appears to be beneficial to recruit high-threshold MUs during training. Moreover, ballistic training methods may promote the recruitment of larger MUs that contain type II fibers at lower thresholds, thus raising the potential for positive strength-power adaptations to occur
Rate Coding
It may be postulated that the increased firing frequency of MUs that results in greater force magnitudes and RFD may aid strength-power development. Previous research indicated that 12 weeks of ballistic training may enhance MU firing frequency
Motor Unit Synchronization
RT may increase MU synchronization and force production. Training strategies that include heavy RT and/or ballistic-type movements may improve MU synchronization
Neuromuscular Inhibition
Heavy RT may down-regulate Ib afferent feedback to the spinal motoneuron pool, leading to reductions in neuromuscular inhibition and increased force production. Further research reported an enhanced neural drive from both the spinal and supraspinal levels following RT that simultaneously decreased neuromuscular inhibition, increased power output via reciprocal inhibition during complex training, downregulated recurrent inhibition following explosive-type training, and enhanced RFD
Periodization and Programming
There are a number of periodization methods that can improve muscular strength; however, single- or multi-targeted block periodization (BP) may produce the greatest improvements in strength and related force–time characteristics (e.g., RFD and power)
Resistance Training Methods
Each of following (table 2) may be implemented concurrently or during specific times of the training year to elicit the desired physiological adaptations.
While a variety of RT methods exist, bilateral training, eccentric training (ET), accentuated eccentric loading (AEL), and variable RT may have the greatest potential to improve muscular strength. In contrast, bodyweight exercise, isolation exercises, plyometrics, unilateral exercise, and kettlebell training may be limited in their potential to produce large maximal strength improvements but are still relevant to strength development by challenging time-limited force expression and differentially challenging motor demands
Loading Strategies
The extant literature suggests that Training to Failure (TF) is not necessary when the goal is to improve muscular strength. Combining heavy and light loads may produce the desired strength adaptations while underpinning RFD and power characteristics that are important to sport performance
Exercise Set Considerations
Multiple sets may produce superior training benefits compared to single sets; however, prescription of sets should be based on an athlete’s training status and the dose–response relationship for muscular strength development. While cluster-sets (CS) may benefit hypertrophy and power adaptations, they may not benefit strength improvements
Rest Intervals
Inter-set rest intervals ranging from 2 to 5 min may provide the greatest strength power benefits; however, rest interval length may vary based on an athlete’s training age, fiber type, and genetics
Training Status Considerations
Weaker/less-skilled athletes should focus on developing a strength foundation before power-type exercises and training methods (plyometrics and potentiation complexes) are emphasized. In contrast, stronger/more-skilled athletes may begin to emphasize power-type exercises and training strategies while maintaining/improving their strength levels.
References
1. Suchomel, T.J., et al., The Importance of Muscular Strength: Training Considerations. Sports Medicine, 2018.